It’s by now a rote observation that the ascendancy of Donald Trump to the American presidency has emboldened white supremacists and bigots, but it’s an observation that needs to be reiterated constantly lest it is ignored or normalized.

For many Americans, the idea that Nazis would one day proudly march through our streets was a nightmare that vanished in 1945. Yet here we are. To date, the president has still failed to offer a full-throated denunciation of the despicable racists who have come violently crawling out of their cellars since he won the election. He knows most if not all of them voted for him, so he’s content to let them thrive.

Now, a man who lived through the horrors of the original Nazis is speaking out. Steven B. Jacobs, a survivor of the Holocaust gave an interview with Newsweek in which he sounded the alarm about the current state of American politics.

Jacobs, 79, is the youngest living survivor of the genocide and came to the United States a few years after Buchenwald — the infamous concentration camp where he was imprisoned — was liberated.

He’s deeply worried about the direction of the United States. “Things just go from bad to worse every day. There’s a real problem growing,” he told Newsweek. “It feels like 1929 or 1930 Berlin,” Jacobs went on to say.

Jacobs, an architect, said that he knows Trump personally from working in the New York real estate scene. He believes that the president has no real ideas, is only out to help himself, and is a “sick, very disturbed individual.”

When confronted with the question of whether or not Trump is a fascist, Jacobs said that Trump can’t really be one because he lacks the “mental power” to even understand what fascism is in the first place. In other words, Trump is evil but not intelligent to have a larger ideology underpinning his evil.

Jacobs zeroed in on the state of political discourse today, taking specific aim at the fact that horrible people now feel comfortable saying horrible things in public. Trump has moved the Overton Window to the point where things that were once taboo, regressive ideas that were once too heinous to voice aloud, are now par for the course.

“Things that couldn’t be said five years ago, four years ago, three years ago—couldn’t be said in public—are now normal discourse. It’s totally unacceptable,” Jacobs said.

Jacobs also reflected on how the country could have gotten to where it is today and the delusions that many of us had under President Obama, falsely believing that we were headed uninterrupted towards a brighter, more egalitarian society. Instead, widespread racist backlash and grievance politics gave us Trump.

“We thought our country had changed. In fact, it didn’t. We were operating on a misconception. ‘My god, we elected a black president in the United States! Look how far we’ve come!’ We haven’t,” he said.

When people like Jacobs — who have witnessed the darkness of history firsthand — speak up, we would be wise to listen. The world is always just a few bad turns away from the horrors of the 20th century. If we aren’t vigilant, the Trump presidency could be just the beginning of our worries.